There's no limit on the number of rows. I've checked that exact matches like *1 and *93 work correctly for me.

What I suspect is happening is that your ATA is not passing through the call. Some ATAs, such as the Sipura/Linksys ones, treat * prefixed numbers as special codes to perform actions on the ATA. You can turn that behaviour off somewhere in the ATA's settings.

On my Sipura SPA3000, found them under Regional->Vertical Service Activation Codes . There are a bunch of them. Could not find a single toggle to disable them all. So maybe easier is to use a different schema for speedials on ss.